Eclipse Modeling Framework

EMF relates modeling concepts directly to their implemenations. It is
a framework and code generation facility that allows it to define a
model in java interfaces, uml or xml schema and generate the others. EMF
is described as that is is in between the "I don't need modeling" and
the "Modeling rules" crowds. [1]

The Ecore (Meta Model)

The model used to represent models in EMF is called Ecore. Ecore is itself an EMF model, and thus is its own metamodel. [1]

Summary [1]:

Ecore and its XMI serialisation is the center of the EMF world.

An Ecore model can be created from any of at least three sources: a UML model, an XML Schema, or annotated Java interfaces.

Java implementation code and, optionally, other forms of the mocel can be generated from an Ecore model.

Other forms of models (in the book they take the example of an RDB schema) are possible to generate the Ecore Model [1].